If you're in the market for a new sleeping bag liner, Cocoon has a wide variety of options to choose from. They have liners made of silk, fleece, cotton, flannel and even microfiber. But if you want the absolute best of the bunch, then check out their Merino wool Mummy Liner, which offers warmth, breathability, and unbelievable comfort.
For those who aren't familiar with sleeping bag liners, they seamlessly slide inside your existing bag, adding extra layer of insulation. Each type of fabric delivers a different type of performance. For instance, the silk version packs down to a small size, provides a few degrees of extra warmth and responds well to changing temperatures. Cotton, on the other hand, is machine washable, very durable and breathes nicely. Merino wool offers most of those qualities and and a few of its own.
As the names implies, the Cocoon's Merino wool Mummy Liner is shaped nicely to fit inside your mummy sleeping. That includes a nicely rounded top to fit inside your bag's hood without bunching up in the process.
Cocoon says that the Mummy Liner will add approximately 7ºC or 12. 6ºF to any sleeping bag that it is added to. That's a substantial amount of extra warmth out of a product that doesn't add much weight to your backpack, and could potentially keep you from actually buying another sleeping bag for your outdoor adventures. Want to take that cool weather bag on a winter camping trip? Just add a bag liner and you're good to go.
Using Merino wool in this particular liner was definitely an inspired choice. Not only is that particular fabric soft and comfortable, it also happens to be very warm. On top of that, it breathes very well, making it easy to regulate temperature throughout a long nights sleep. Merino wool also happens to have natural qualities that keep it from holding on to unwanted smells, which can come in handy on extended backpacking trips.
This particular liner is comfortable enough that it can even be used on its own in warmer weather. The Merino wool is incredibly soft against the skin, and because of its natural ability to breathe, it works great as an extremely lightweight stand-alone sleeping bag for summer camping trips. When camping in environments that are too warm for a traditional sleeping, bag, you can pair this liner with a sleeping pad, and get a good night's sleep without overheating.
Putting this liner to the test, I came away impressed with a couple of things. First, the Merino wool is very durable, resisting tears and abrasions, and coming away unscathed, even after using it on a couple of camping trips. I also appreciated how stretchy the fabrics were, making it easy to sleep without feeling to restricted.
If you're an ultralight traveler or hiker who counts every ounce, there are other options available that are both smaller and lighter weight. At 495 grams (17.4 ounces), this is a rather heavy bag liner compared to some of the other options in the Cocoon line-up. When placed inside of its included stuff sack, it also carries a larger footprint than some of the other options as well. But it does deliver on the promise of 12+ extra degrees of warmth, and a super-comfortable nights sleep. If those are qualities you find that you need while backpacking, then this Mummy liner is perfect for your needs.
At $99.95, the liner isn't the most affordable option on the market. But it does happen to offer some of the best performances you'll find anywhere. Merino wool is one of the best fabrics available for use in our outdoor adventures, and I am happy to see it migrate from clothing, to other products as well.